1. Technical Field
The present invention relates to a technology for remotely controlling a control target connected with a network.
2. Background Art
A Wake on LAN (hereinafter described as “WOL”) technology is known as a technology by which a user remotely turns on a power supply of a network device such as a personal computer (PC) and a server. In the technology, a wake up packet is transmitted to a device to which no power is supplied and the device which receives the wake up packet is activated.
Magic Packet technology is known as one of related arts which specifically realize a WOL technology. In the technology, a packet called a Magic Packet is used as a wake up packet. A user transmits an instruction packet including a predetermined command to a remote control apparatus. Upon receipt of the instruction packet, the remote control apparatus transmits a Magic Packet to a device which a user intends to turn on with remote controlling (hereinafter described as power-on target device). A network interface of the power-on target device turns on a power supply thereof, upon receipt of the Magic Packet addressed to the device. For example, Magic Packet technology is described in “Magic Packet Technology White Paper (published by Advanced Micro Devices, Inc. on November 1995)” (hereinafter described as “reference 1”).
FIG. 1A shows an exemplary configuration of a wake up packet. FIG. 1B shows information included in each part of a wake up packet. As shown in FIG. 1A and FIG. 1B, in an Ethernet MAC(Media Access Control) frame of a wake up packet, a MAC address of a power-on target device is repeatedly written 16 times in a data area (DATA) (MAC (1) to MAC (16)). In FIGS. 1A and 1B, DA represents a MAC address of a destination device. SA represents a MAC address of a source device. According to a specification of the Ethernet, when the DA is set to FF:FF:FF:FF:FF:FF(all “1”), the MAC frame is treated as a broadcast flame. Further, the reference 1 discloses the configuration shown in FIG. 1A and FIG. 1B.
FIG. 2 shows a related art of a remote control system using a WOL technology. FIG. 2 shows an example of a remote power-on system in which a portable computer 10 located out of a sub network 101 activates servers 121 and 122 or the like in the sub network 101.
In FIG. 2, the portable computer 10 is connected with a remote control apparatus 191 via a router 52, a backbone network 1, a router 100 and a router 181.
The sub network 101 is a sub network connected to the backbone network 1 via the router 100. The sub network 101 accommodates the router 181, the servers 121 and 122 and the remote control apparatus 191. The servers 121 and 122 include a network interface for receiving a wake up packet, respectively.
In the specification, a sub network represents an individual network having an individual network address in a group of networks that are connected with each other via a router. The sub network also includes a network divided by a subnet mask.
Similarly, a sub network 201 is a sub network connected to the backbone network 1 by a router 200. The sub network 201 accommodates a router 281, servers 221 and 222 and a remote control apparatus 291. The servers 221 and 222 include a network interface for receiving a wake up packet.
An operation of each part in a system when the portable computer 10 activates the server 121 is described using FIG. 2.
A user transmits an instruction packet from the portable computer 10 to the remote control apparatus 191 for instructing the remote control apparatus 191 to transmit a wake up packet to the server 121 (i.e. power-on target device). The instruction packet includes a command (e.g. power-on) to the remote control apparatus 191 and an IP(Internet Protocol) address thereof. The instruction packet reaches the remote control apparatus 191 via the router 52, the backbone network 1, the router 100 and the router 181. The remote control apparatus 191 holds information of a MAC address of the servers 121 and 122. When the remote control apparatus 191 receives the instruction packet from the portable computer 10, the remote control apparatus 191 generates a wake up packet in which a MAC address of the server 121 is written in MAC (1) to MAC (16) in a table shown in FIG. 1B. The remote control apparatus 191 broadcasts the wake up packets in the sub network 101.
Here, by broadcasting a wake up packet, the wake up packet reaches not only the server 121 but also the server 122. However, a MAC address of the server 122 is not written in MAC (1) to MAC (16) of the wake up packet. Accordingly, since the server 122 judges that the wake up packet is not addressed to the server 122, the server 122 does not operate any more even if the server 122 receives the wake up packet. The only server 121 performs a power-on operation after receiving the wake up packet including MAC address thereto.
As another related art, Japanese Patent Application Laid-Open No. 2005-109763 (hereinafter described as “reference 2”) discloses a configuration in which a node located out of a network activates a computer in the network using a WOL technology.
The related art described in the background art causes following problems.
1. A wake up packet is a broadcast packet transmitted from a remote control apparatus which generates a wake up packet to a power-on target device. However, since a broadcast packet can not pass through a router and a firewall, a router or a firewall can not be installed between a remote control apparatus and a power-on target device. That is, a remote control apparatus needs to be installed in each network unit which is divided by a router or a firewall.
2. With the increase in size of a corporate network, sub networks which exist in a corporate network are increasing in number. For this reason, power-on target devices which use a wake up packet are separately installed in many sub networks. Accordingly, the number of required remote control apparatuses is increasing along with the increase of sub networks. As a result, in a remote control system mentioned above, an introduction cost of a remote control apparatus increases along with the increase of sub networks.
3. In a remote power-on system using a wake up packet, a remote control apparatus exists for each sub network. Thus, an operator needs to store information about a power-on target device managed by each remote control apparatus into each remote control apparatus. When a power-on target device is moved to another network, an operator has to register again information thereof to each remote control apparatus. Further, it is necessary for a user to acquire, from the operator, the latest information of a remote control apparatus on a sub network on which a power-on target device is installed and to store the information into a portable computer. A user needs to always keep a content of a portable computer correct so that a user can correctly designates a remote control apparatus which manages a power-on target device by using a correct destination address for an instruction packet. As a result, in the remote power-on system above-mentioned, a maintenance/operation cost of a remote control apparatus, after introducing becomes high.
4. Also, a wake up packet cannot pass through a router and a firewall. For this reason, in a remote power-on system of related arts, a remote control apparatus and a power-on target device have to be installed in the same network. Also, in the remote power-on system of related arts, a device in a firewall cannot be activated by a remote control apparatus located out of the firewall even if a remote control apparatus is installed outside of a firewall of a company network.
5. Accordingly, even if an administrator of a network wants to provide a convenient system for users, but it is difficult to introduce a remote power-on system using a WOL technology in view of difficulties in operations and management.
6. In the reference 2 mentioned in the background art, a WOL apparatus is located on a sub network to which a device of power-on target belongs. Accordingly, it is necessary for a user to designate a WOL apparatus installed for each sub network and to transmit an activation instruction packet. The reference 2 does not handle the above-mentioned difficulties.